DE102018102397A1 - Control valve arrangement for indirect pneumatic control - Google Patents

Abstract

The invention relates to a control valve assembly 1 for indirect pneumatic control and a method for controlling a working fluid pressure. In order to provide a control valve assembly 1 and a method of controlling a working fluid pressure by means of a control fluid which allows precise, sensitive and variable speed control without large power losses and control delays, it is contemplated that the control valve assembly 1 comprises two pneumatic, consecutively arranged valve units 2, 3, a working fluid inlet 4 and a control fluid inlet, a working fluid channel 6 connecting the working fluid inlet 4 through both valve units 2, 3 to an outlet 5, each one arranged within a valve cylinder 7, 8 of the first and second valve units 2, 3, displaceable between an open and a closed position Valve piston 9, 10, each one the first and the second valve piston 9, 10 to the closed position biasing spring element 11, 12, respectively connected to the control fluid inlet control pressure chamber 13, 14 for acting on the respective valve piston 9, 10 having a bias of the spring element 11, 12 counteracting control pressure, wherein the first valve unit 2 is formed such that upon application of a control pressure in the first control pressure chamber 13, the first valve piston 9 is moved from the closed to the open position , and wherein in the second valve unit 3 in a blocking and control region 15 of the working fluid channel 6 two opposing, mutually angled valve surfaces 16, 17 are arranged on the surface of the valve cylinder 8 and the valve piston 10 extending along the direction of displacement V in such a way that the valve surfaces 16, 17 when moving the valve piston 10 in the valve cylinder 8 due to a changing control pressure form a differently wide opened valve opening and according to the valve opening the working pressure in response to the control pressure is finely adjustable.

Description

The invention relates to a control valve arrangement for indirect pneumatic control and a method for controlling a working fluid pressure by means of a control fluid in a control valve arrangement for indirect pneumatic control.

From the prior art control valve assemblies for pneumatic control in a variety of refinement from the prior art are known and are used in particular for the control of pneumatic actuators. A special field here concerns the pneumatic control of pneumatically operated motors of hoists.

It is initially known to control the engine, in particular a vane motor, a hoist directly, the pressure of the working fluid, usually compressed air, is directly controlled before the supply line to the pneumatically operated engine. For this purpose, the compressed air provided for the drive is typically passed from a central connection via a hose to a manual control unit and from there to the position of the motor of the hoist, which is usually positioned in the area of a hall ceiling. This makes a long compressed air hose at least from the manual control to hoist arranged at the hall ceiling necessary. However, these hoses, which must endure the full working pressure of the working fluid, are relatively thick and heavy, making them difficult to handle and complicating operation. Furthermore, leads a correspondingly long hose between the hand control and hoist to the hose length increasingly greater power losses and to a control delay, whereby a precise and sensitive control of a load on the hoist is no longer possible.

In addition, from the prior art indirect controls are known in which the working fluid is connected directly to a control valve assembly on the engine, wherein the control by means of a control fluid, usually also compressed air at a lower pressure than the pressure of the working fluid, takes place. It is common that by means of applied to a manual control fluid control only switching on and off of the working fluid by means of the control valve assembly on the pneumatic motor, while the working pressure and thus the speed of the hoist are fixed and adjustable by means of a set screw on the control valve assembly. However, this has the disadvantage that a change in the speed of the hoist is not readily possible and thus only either a slow start and sensitive lifting or alternatively a rapid lifting of loads is possible. In particular, when transporting heavy loads over high altitudes but both a high lifting speed, as well as a sensitive control for lifting and stopping the load is necessary.

It may therefore be considered an object of the invention to provide a control valve assembly and method for controlling a working fluid pressure by means of a control fluid, which allows precise, sensitive and variable speed control without large power losses and control delays.

The object is achieved by a control valve assembly according to claim 1 and a method according to claim 10. Advantageous developments of the invention are specified in the dependent claims.

The control valve arrangement according to the invention for indirect pneumatic control, in particular a pneumatically operated multi-disk motor of a hoist, comprises two pneumatic, functionally successively arranged valve units, a working fluid inlet and a control fluid inlet and a working fluid channel connecting the working fluid inlet through both valve units to an outlet, the outlet in particular for delivery the working fluid is provided to a vane motor of a hoist. At each of the two valve units each one arranged within a valve cylinder, slidable between an open and a closed position valve piston is provided, wherein on each of the two valve piston acts on the closed position of the valve unit towards biasing spring element. Both valve units furthermore each have a control pressure chamber connected to the control fluid inlet for acting on the respective valve piston with a control pressure counteracting the bias of the spring element in order to move the valve piston against the force of the spring element into an at least partially open position.

In this case, the first valve unit is formed such that when creating any control pressure greater than 0 bar in the control pressure chamber, the valve piston is moved from the closed to a fully open position. In the second valve unit, in a blocking and control region of the working fluid channel, two opposing, mutually angled valve surfaces on the surface of the valve cylinder and the valve piston extending along the direction of displacement are arranged such that the valve surfaces during displacement of the valve piston due to the applied control pressure in dependence of the control pressure associated displacement position of the valve piston in the valve cylinder form a differently wide open valve opening and according to the valve opening of the working pressure in dependence of the control pressure is finely adjustable.

The invention also relates to a hoist having a pneumatically operated vane motor and a control valve arrangement according to the invention arranged in front of it.

In the inventive method for controlling a working fluid pressure by means of a control fluid, in particular in a control valve arrangement according to the invention for indirect pneumatic control, preferably for a pneumatically driven vane motor of a hoist, first a working pressure is applied by means of a working fluid to a working fluid inlet and a control pressure in a control fluid, in particular adjusted by means of a sensitive valve of a manual control, as well as a control fluid inlet loaded with the control pressure. The control fluid under the control pressure is introduced into a respective control fluid chamber of two pneumatic valve units, wherein the control fluid can move a biased by a spring element to a closed position, disposed within a valve cylinder valve piston to an open position.

In this case, by applying any control pressure in the first control pressure chamber, the first valve piston is displaced from the closed to the open position, whereby the working fluid can flow through the first, open valve unit to the second valve unit through a working fluid channel connected to the working fluid inlet. In this case, the application of the control pressure in the second control pressure chamber to a displacement of the second valve piston against the force of the spring element in a control pressure associated position of the valve piston in the valve cylinder between the closed and the open position, whereby the working fluid through the working fluid channel in the second valve unit between two opposing, mutually angled and flows on the surface of the valve cylinder and the valve piston along the displacement direction extending valve surfaces, wherein a formed between the valve surfaces valve opening in the working fluid passage in accordance with the control pressure is correspondingly finely adjustable.

The control valve arrangement according to the invention and the method according to the invention enable in a particularly simple manner a precise, sensitive and continuous control, wherein the pressure of the working fluid can be controlled at the outlet, for example, over a wide range proportional to the pressure of the control fluid. In addition, a variation of the pressure of the working fluid in operation is made possible by a pressure adjustment of the control fluid in a simple manner, whereby, for example, the speed of a driven by the working fluid motor of a hoist is infinitely and sensitively variable. Furthermore, by the indirect control by means of a control fluid dependent on the hoist altitude and the distance to the manual control power loss is avoided. Finally, there are also no control delays due to direct control of the working fluid pressure with a subsequent large volume of working fluid in a long hose or the like.

In principle, the control valve arrangement is an assembly within which the pressure of a working fluid which has passed through and possibly is blocked can be controlled by means of the pressure of a control fluid. Thus, according to the invention, it is a device for indirect control. In this case, the control valve arrangement may be an independent device and in particular in a supply line for a working fluid to an actuator, in particular a pneumatic motor, may be arranged. Alternatively, however, the control valve arrangement can also be part of a further device and in particular be integrated in a hoist. Preferably, the control valve assembly is an exclusively pneumatically operated device, that is, no additional operating medium and / or electricity is necessary for operation.

Each of the pneumatic valve units comprises at least one, preferably exactly one valve, which can be switched or controlled by means of a fluid, in particular a gas pressure. Particularly preferably, each valve unit is formed by a valve which is operated exclusively pneumatically, wherein this preferably excludes no spring elements in the interior of the valve unit, but particularly preferably relates only to the operation from the outside. The first and second valve unit are preferably arranged directly adjacent to each other, in a common housing, wherein particularly preferably the two valve cylinders are arranged parallel to each other and / or next to each other and very particularly preferably with respect to length and / or diameter identical to each other. In this case, the valve units are arranged functionally one behind the other, that is, the working fluid supplied to the control valve arrangement passes first to the first valve unit and then, preferably with the first valve unit in an open position, into the second valve unit.

The pressurized fluids, the working fluid and / or the control fluid, may in principle be any liquid or gas. Although an operation with a hydraulic working and / or control fluid is conceivable, however, a purely pneumatic operation is preferred. Particularly preferably, the pressurized fluids are each compressed air. In principle, the pressure of the working and / or control fluid can be chosen as desired. Preferably, the pressure of the working or operating fluid provided is between 0 bar and 10 bar, more preferably at most 6 bar and most preferably exactly 6 bar, so that at the working fluid inlet of the control valve assembly is applied a constant pressure of about 6 bar. The maximum control pressure, ie, the pressure of the control fluid, is preferably also 6 bar, wherein the control pressure is particularly preferably between 1 bar and 6 bar by means of a control valve, in particular in a manual control, variable. Accordingly, preferably at the control fluid inlet of the control valve arrangement, a pressure of at most 6 bar and preferably between 1 bar and 6 bar.

In principle, the working fluid channel has the task of connecting the working fluid inlet to the outlet for the working fluid within the control valve arrangement and thereby guiding the control fluid through both valve units in such a way that the flow rate or the volume flow of the working fluid can be varied by means of both valve units. For this purpose, the working fluid channel preferably extends through in each case a blocking and control region of the two valve units and in particular by the respective valve opening, which is formed by the two valve surfaces of the valve cylinder and the valve piston. Preferably, the working fluid channel connects the first and second valve units with each other such that the working fluid can flow directly from the first to the second valve unit. Particularly preferably, no further components, in particular no valves and / or branches, are arranged in the working fluid channel between the first and the second valve unit.

The spring element may in principle be any component or any assembly which is suitable for biasing the valve piston within the valve cylinder toward a closed position of the valve unit. In this case, the spring element is preferably a compression spring, particularly preferably a spiral spring, and / or formed in one piece. Further preferably, one side of the spring element is supported against a front or end side of the valve cylinder and / or the other side of the spring element at one end or an end face of the valve piston. Most preferably, one end of the spring element is arranged at least in sections in a bore of the valve piston. Also preferably, the bore is arranged at the end or on the end face of the valve piston and / or in particular has a depth selected so that the spring element are completely pressed into the bore and then the end face of the valve piston come into abutment with an end face of the valve cylinder can, which is determined in a particularly simple manner, the maximum displaceability of the valve piston with respect to the valve cylinder in this direction.

Preferably, the thickness of the first spring element is chosen such that the valve piston reliably closes the working fluid channel without applied pressure of the control fluid and particularly preferably at the same time such that upon reaching a predetermined minimum pressure of the control fluid, preferably from 1.2 to 1.3 bar, the Valve piston against the force of the spring element is pushed so far in the direction of the open position in the valve cylinder that a complete opening is made possible by means of the increasing pressure of the working fluid in the first valve unit. In principle, however, the minimum pressure for opening the valve piston can also be chosen differently. Preferably, the thickness of the second spring element is selected such that a displacement of the valve piston takes place to the desired extent at a predetermined control pressure, in particular a complete displacement exactly within the possible pressure limits of the control pressure, for example between 1 bar and 6 bar. In order to allow control of the pressure of the working fluid by means of the control valve arrangement, at least the second control pressure chamber must be completely separated from the working fluid channel. Preferably, the first control fluid chamber is also completely separated from the working fluid channel.

Preferably, an arbitrarily strong control pressure or an arbitrary control pressure above a minimum pressure in the first control pressure chamber is sufficient to completely open the first valve unit. The first valve unit is thus operated upstream as a check valve of the second valve unit and provides u.a. Advantageously, that no permanent pressure is applied to the second valve unit when no control pressure acts on the control valve assembly. In addition, the first valve assembly forms a safety valve to provide double safety adjacent the second valve assembly against undesirable release of working pressure at the outlet. Preferably, the first valve unit can only be switched between a closed and an open state, that is, it is a two-state valve.

Also, the second valve unit is preferably formed such that it can completely block the working fluid. In order to allow the working fluid to pass through to the desired extent, the second valve unit has a valve opening which can be adjusted by displacing the valve piston in the valve cylinder. In this case, the valve opening is formed on one side by a valve surface of the valve piston and on an opposite side by a valve surface of the valve cylinder. To a displacement of the valve piston, a change in the size of To allow valve opening, the two valve faces are arranged angled to each other, so that increases the distance between the two valve surfaces when moving the piston or reduced. In order to enable a sensitive adjustment, each of the valve surfaces extends on a surface of the valve piston or the valve cylinder at least in sections along the direction of displacement. With a suitable selection of the spring strength of the valve unit, it is possible to provide a specific position of the Ventilkobens in the valve cylinder between the closed and the open position for each possible control pressure, so that according to the valve opening the working pressure in response to the control pressure is adjusted according to fine.

In an advantageous development of the control valve arrangement according to the invention, at least one of the two valve surfaces of the second valve unit has at least two, preferably exactly two consecutive sections, wherein particularly preferably the angle between the valve surfaces in the first, the closed position following section is smaller than the angle of the valve surfaces in the second, adjacent to the open position area, whereby a particularly sensitive start and slow lifting and lowering is possible with a hoist. In this case, one of the two valve surfaces preferably has a changing angle between the first and the second section, and particularly preferably the other valve surface is formed without changing the angle. Further preferably, the two portions of a valve surface are clearly separated from each other, that is, the angle between the portions does not change continuously, but abruptly or at a position. Also preferably, the angle of the valve surfaces in the second section is at least twice as large, more preferably at least five times as large and most preferably at least ten times as large as the angle of the valve surfaces in the first section. Accordingly, in the second section of the valve surfaces preferably the diameter of the valve piston or the distance of the two opposing valve surfaces at least twice, more preferably at least five times and most preferably at least ten times as large as in the first section. Particularly preferably, both sections are formed such that they allow control of the flow rate of the working fluid between a fully locked state and a fully open state, initially a slow and sensitive start and higher control pressure a rapid lifting of a load by means of a hoist is possible. Most preferably, the two sections are additionally controlled to the closed and the open state.

According to a preferred embodiment of the control valve arrangement according to the invention, the two valve surfaces in the first and / or second section, at least in relation to each other, preferably each formed linearly extending, wherein the angle between the two valve surfaces of the first section preferably between 0.1 ° and 15 °, more preferably between 1 ° and 10 ° and most preferably between 2 ° and 7 ° and the angle of the second section between 5 ° and 85 °, more preferably between 10 ° and 75 ° and most preferably between 20 ° and 65 ° , In particular, the angle in the first section is 2 ° and / or the angle in the second section is 45 °. Further preferably, both valve surfaces extend in the first and / or second portion at a constant angle to each other along the surface of the valve cylinder or the valve piston, so that the distance between the two valve surfaces continuously increases, in particular from the closed position to the open position.

An embodiment of the control valve arrangement provides that at least one of the two valve surfaces in the first and / or second portion is formed non-linearly extending, wherein the angle between the two opposite valve surfaces of the valve piston and the valve cylinder preferably increases between the closed and the open position and thereby the angle of the first section further preferably between 0.1 ° and 15 °, more preferably between 1 ° and 10 ° and most preferably between 2 ° and 7 ° and the angle of the second section between 5 ° and 85 °, more preferably between 10 ° and 75 ° and most preferably between 20 ° and 65 °. Most preferably, one of the valve surfaces of the valve piston or the valve cylinder is formed non-linearly extending in one or both sections, while the opposite valve surface of the valve cylinder or the valve piston is linear.

In general, a profile of the valve surfaces in relation to one another is preferred with a valve opening which increases toward the open position of the valve piston. It is also generally preferred that in at least one section and particularly preferably in both sections, the valve face of the valve piston or the valve cylinder is arranged parallel to the adjustment of the valve piston in the valve cylinder, while the other, opposing valve face arranged at an angle thereto with a linear or non-linear course is. Particularly preferred is an embodiment with a profile of the valve surface with a first linear section with a small angle and a second linear section with a larger angle.

In a preferred embodiment of the control valve arrangement according to the invention, the first section and / or the second section of the valve surfaces extends over at least 15%, preferably at least 25%, more preferably at least 30% and most preferably over at least 40% of the maximum displacement of the valve piston with respect to the valve cylinder, whereby a particularly sensitive control can be achieved. Also preferably, the first section extends over a maximum of 80%, preferably 60%, more preferably 50% and most preferably 40% of the maximum adjustment. Further preferably, both sections together extend over at least 50%, more preferably at least 75%, and most preferably at least 80% of the maximum adjustment length of the valve piston.

Furthermore, an embodiment of the control valve arrangement is preferred in which at least the second valve piston, preferably also the first valve piston, is rotationally symmetrical about an axis along the adjustment and the corresponding valve cylinder has a round cross section, so that the valve opening has the shape of an annular gap. Accordingly, at least one valve surface preferably has a conical shape, while the second valve surface is also preferably cylindrical or conical.

Also preferred is an embodiment of the control valve arrangement in which the first and / or second control pressure chamber in the region of the spring element opposite the end of the respective valve piston is arranged and / or the working fluid channel in the first and / or in the second valve unit between the region of the spring element and the Area of the control pressure chamber is arranged. Particularly preferably, the working fluid channel surrounds the respective valve piston within the valve cylinder in sections on all sides. Further preferably, the working fluid channel is formed in sections by the valve cylinder.

In an advantageous development of the control valve arrangement according to the invention a hand control unit is arranged in front of the control fluid inlet, which has a hand controller, by means of which the control pressure of the control fluid is infinitely adjustable, the hand controller particularly preferably comprises a handbetätigbares gas valve by means of which the control pressure is infinitely and sensitively adjustable.

Finally, the control valve arrangement preferably has exactly one single control fluid inlet, which is connected to the two control pressure chambers in the interior of the control valve arrangement, so that the control pressure is always the same in both control pressure chambers. Particularly preferably, the control valve arrangement also has only exactly one working fluid inlet and / or one working fluid outlet.

• 1 eine Schnittansicht einer Steuerventilanordnung mit zwei geschlossenen Ventileinheiten,
• 2 eine vergrößerte Schnittansicht eines Sperrbereichs der zweiten Ventileinheit der in 1 dargestellten Steuerventilanordnung,
• 3 eine Schnittansicht der in 1 dargestellten Steuerventilanordnung mit einer geöffneten ersten Ventileinheit und einer geschlossenen zweiten Ventileinheit, und
• 4 eine Schnittansicht der in 1 dargestellten Steuerventilanordnung mit einer voll geöffneten ersten Ventileinheit und einer teilweise geöffneten zweiten Ventileinheit,
• 5 eine Schnittansicht der in 1 dargestellten Steuerventilanordnung mit zwei geöffneten Ventileinheiten.

An embodiment of the control valve assembly according to the invention will be explained below with reference to the drawings. In the figures show:

• 1 a sectional view of a control valve assembly with two closed valve units,
• 2 an enlarged sectional view of a locking portion of the second valve unit of in 1 illustrated control valve assembly,
• 3 a sectional view of in 1 illustrated control valve assembly having an opened first valve unit and a closed second valve unit, and
• 4 a sectional view of in 1 illustrated control valve assembly having a fully open first valve unit and a partially opened second valve unit,
• 5 a sectional view of in 1 illustrated control valve assembly with two open valve units.

At an in 1 illustrated control valve assembly 1 for indirect pneumatic control of the working pressure for a pneumatic vane motor of a hoist are a first and a second valve unit 2 . 3 arranged parallel to each other in a common housing.

Each of the two valve units 2 . 3 is formed as a spring-biased, pneumatically operated valve. Accordingly, in each of the valve units 2 . 3 a sliding valve piston 9 . 10 in a valve cylinder 7 . 8th arranged such that a through the valve unit 2 . 3 guided pressurized fluid, in particular compressed air, by means of a surface portion of the valve cylinder 7 . 8th and the valve piston 9 . 10 can be locked or regulated.

The valve piston 9 . 10 is on one side with a coil spring 11 . 12 biased to a closed position with one end of the coil spring 11 . 12 against a round face of the valve cylinder 7 . 8th is supported while the other end within a bore in the valve piston 9 . 10 is fixed. On the other end e of the valve piston 9 . 10 is in the valve cylinder 7 . 8th a control pressure chamber 13 . 14 educated. The control pressure chambers 13 . 14 both valve units 2 . 3 are connected in common with an inlet for a control compressed air flow, so that in the control pressure chamber 13 . 14 a pressure can be built up, the spring tension of the spiral spring 11 . 12 counteracts and by acting on the end face of the valve piston 9 . 10 With the control pressure is a displacement of the valve piston 9 . 10 allows.

The control valve unit 1 has a working air inlet 4 and a corresponding outlet 5 on, which provides a pressure-controlled compressed air flow for the vane motor of the hoist. The outlet 5 is via a working air duct 6 with the working air inlet 4 connected, wherein the working pressure air duct 6 in succession through both valve units 2 . 3 leads and in each case by means of the valve units 2 . 3 in a restricted and controlled area 15 is lockable and adjustable.

On the second valve piston 10 and the associated valve cylinder 8th is each a valve surface 16 . 17 arranged in the closed state of the valve unit 2 . 3 abut each other. Both valve surfaces 16 . 17 are arranged so angled to each other that when moving the valve piston 10 in the valve cylinder 8th with increasing displacement, an enlarging valve opening in the form of an annular gap is formed.

In 1 is a control valve assembly 1 with both valve units 2 . 3 shown in the closed position, so that the first valve unit 2 the working pressure air flow already shortly after the working air inlet 4 shut off and on the second valve unit 3 no pressure in the area of the working compressed air duct 6 is applied. In this state of the control valve assembly 1 There is also no control pressure or the control pressure of the control compressed air in the control pressure chambers 13 . 14 is below a specified threshold of about 1.2 bar to open the valve units 2 . 3 ,

In 3 is a control valve assembly 1 shown in a state that only briefly or exactly upon reaching a threshold value of the control pressure to open the valve units 2 . 3 occurs. The first valve unit 2 is fully open while the second valve unit 3 is still closed. The one in the first control air pressure chamber 13 applied control pressure acts on the first coil spring 11 so far counter that the valve opening of the first valve unit 2 just opened by the two valve faces 16 . 17 the first valve unit 2 out of contact.

With increasing control pressure now also the second valve piston 10 the second valve unit 3 against the spring force of the coil spring 12 shifted to the open position, wherein the spring force is selected such that in a predefined pressure range, preferably between 1 bar and 6 bar, the valve piston 10 over the maximum adjustment path W is moved.

In order to initially enable a sensitive control and with increasing control pressure then a rapid and powerful release of the working air pressure, are the valve surfaces 16 . 17 the second valve unit 3 with one inside the control area 17 of the valve piston 10 changing angles a . b formed (see 2 ). Here is the valve surface 16 of the valve cylinder 8th as a linear cylindrical surface as part of the wall of the valve cylinder 8th educated. The valve surface 17 of the valve piston 10 has two mutually angled sections A . B on, each also at an angle a . b to the opposite valve surface 16 are arranged. Both sections A . B have a linear course. The angle a the first portion of the valve surface 17 to the opposite valve surface 16 is 5 °, while the corresponding angle b of the second section B 45 °. The two sections A . B extend over 85% of the maximum adjustment path W of the valve piston 10 in the valve cylinder 8th ,

In 4 is a control valve assembly 1 with the first valve unit 2 in the fully open position and the second valve unit 3 shown in a partially open position, wherein the working pressure air through a through the control surfaces 16 . 17 the second valve unit 3 formed annular gap is passed and a reduced volume flow through this annular gap through the working pressure air duct 6 from the working air pressure inlet 4 to the outlet 5 the control valve assembly can flow.

In 5 is finally a control valve assembly 1 with both valve units 2 . 3 shown in the fully open position, with the working pressure air through the control surfaces 16 . 17 the two valve units 2 . 3 unhindered by the working pressure air duct 6 from the working air pressure inlet 4 to the outlet 5 the control valve assembly can flow.

LIST OF REFERENCE NUMBERS

1

Control valve assembly

2

first valve unit

3

second valve unit

4

Working fluid inlet

5

outlet

6

Working fluid channel

7

first valve cylinder

8th

second valve cylinder

9

first valve piston

10

second valve piston

11

first spring element

12

second spring element

13

first control pressure chamber

14

second control pressure chamber

15

Locking and control range

16

first valve surface

17

second valve surface

A

first section

B

second part

e

End of the valve piston

F

Area of the spring element

S

Area of the control pressure chamber

V

adjustment

W

maximum adjustment path

a

Angle of the first section

b

Angle of the second section

Claims (10)

Control valve arrangement (1) for indirect pneumatic control, in particular a pneumatically operated multi-disk motor of a hoist, with two pneumatic valve units (2, 3) arranged one behind the other, a working fluid inlet (4) and a control fluid inlet, a working fluid channel (6) connecting the working fluid inlet (4) through both valve units (2, 3) to an outlet (5), each one of a valve piston (9, 10) arranged within a valve cylinder (7, 8) of the first and second valve unit (2, 3), displaceable between an open and a closed position, each one of the first and the second valve piston (9, 10) biasing towards the closed position spring element (11, 12), - One respectively connected to the control fluid inlet control pressure chamber (13, 14) for acting on the respective valve piston (9, 10) with a bias of the spring element (11, 12) counteracting control pressure, wherein - The first valve unit (2) is formed such that upon application of a control pressure in the first control pressure chamber (13) of the first valve piston (9) is moved from the closed to the open position, and wherein - In the second valve unit (3) in a blocking and control region (15) of the working fluid channel (6) two opposing, mutually angled valve surfaces (16, 17) on the valve cylinder (8) and the valve piston (10) so along the direction of displacement (V) are arranged extending, that the valve surfaces (16, 17) when moving the valve piston (10) in the valve cylinder (8) form a differently wide open valve opening due to a changing control pressure and finely adjustable according to the valve opening width of the working pressure in response to the control pressure is. Control valve arrangement according to Claim 1 , characterized in that at least one of the two valve surfaces (16, 17) of the second valve unit (3) has two successive sections (A, B), wherein the angle (a) between the valve surfaces (16, 17) in the first, closed position following section (A) is smaller than the angle (b) of the valve surfaces (16, 17) in the second, adjacent to the open position region (B). Control valve arrangement according to Claim 1 or 2 , characterized in that the two valve surfaces (16, 17) in the first and / or second section (A, B) are linearly formed, wherein the angle (a, b) between the two valve surfaces (16, 17) between 0, 1 ° and 10 °. Control valve arrangement according to one of the preceding claims, characterized in that at least one of the two valve surfaces (16, 17) in the first and / or second portion (A, B) is formed non-linearly extending, wherein the angle (a, b) between the two valve surfaces (16, 17) increases between the closed and the open position and is between 0.1 ° and 45 °. Control valve arrangement according to one of the preceding claims, characterized in that the first section (A) and / or the second section (B) of the valve surfaces (16, 17) in each case over at least 25% of the maximum adjustment path (W) of the valve piston (10). extends in relation to the valve cylinder (8). Control valve arrangement according to one of the preceding claims, characterized in that at least the second valve piston (10), preferably also the first valve piston (9) is formed rotationally symmetrical and the corresponding valve cylinder (8, 7) has a round cross-section, so that the valve opening the shape an annular gap has. Control valve arrangement according to one of the preceding claims, characterized in that the first and / or second control pressure chamber (13, 14) in the region of the spring element (11, 12) opposite end (E) of the respective valve piston (9, 10) is arranged and / / or the working fluid channel (6) in the first and / or in the second valve unit (2, 3) between the region (F) of the spring element (11, 12) and the region (S) of the control pressure chamber (13, 14) is arranged. Control valve arrangement according to one of the preceding claims, characterized in that a manual control unit before the Control fluid inlet is arranged, which has a hand controller, by means of which the control pressure of the control fluid is infinitely adjustable. Control valve arrangement according to one of the preceding claims, characterized by a single control fluid inlet, which is connected in the interior of the control valve arrangement (1) with both control pressure chambers. Method for controlling a working fluid pressure by means of a control fluid in a control valve arrangement (1) for indirect pneumatic control, comprising the steps of: Applying a working pressure by means of a working fluid to a working fluid inlet (4), Controlling the pressure in a control fluid, in particular by means of a sensitive valve of a manual control, and loading a control fluid inlet with the control pressure, - Introducing control fluid in each case a control fluid chamber (13, 14) of a pneumatic valve unit (2, 3), wherein the control fluid by a spring element (11, 12) biased to a closed position, within a valve cylinder (7, 8) arranged valve piston (9, 10) can move to an open position, wherein the application of a control pressure in the first control pressure chamber (13) shifts the first valve piston (9) from the closed to the open position, whereby the working fluid is conveyed through a working fluid passage (6) connected to the working fluid inlet (4) through the first, open valve unit (10). 2) to the second valve unit (3) can flow, wherein - The application of the control pressure in the second control pressure chamber (14) to a displacement of the second valve piston (10) against the force of the spring element (12) in a control pressure associated position of the valve piston (10) in the valve cylinder (8) between the closed and the open position, whereby the working fluid through the working fluid channel (6) in the second valve unit (3) between two opposite, mutually angled and on the surface of the valve cylinder (8) and the valve piston (10) along the direction of displacement (V) extending Valve surfaces (16, 17) flows through, wherein between the valve surfaces (16, 17) formed valve opening in the working fluid channel (6) in response to the control pressure is correspondingly finely adjustable and controls the outlet (5) applied pressure of the working fluid.

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